// XMLFilterImpl.java - base SAX2 filter implementation.
// Written by David Megginson, sax@megginson.com
// NO WARRANTY! This class is in the Public Domain.
// $Id: XMLFilterImpl.java,v 1.4 2000/05/05 17:50:37 david Exp $
package org.xml.sax.helpers;
import java.io.IOException;
import org.xml.sax.XMLReader;
import org.xml.sax.XMLFilter;
import org.xml.sax.InputSource;
import org.xml.sax.Locator;
import org.xml.sax.Attributes;
import org.xml.sax.EntityResolver;
import org.xml.sax.DTDHandler;
import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.SAXNotRecognizedException;
/**
* Base class for deriving an XML filter.
*
* <blockquote>
* <em>This module, both source code and documentation, is in the
* Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
* </blockquote>
*
* <p>This class is designed to sit between an {@link org.xml.sax.XMLReader
* XMLReader} and the client application's event handlers. By default, it
* does nothing but pass requests up to the reader and events
* on to the handlers unmodified, but subclasses can override
* specific methods to modify the event stream or the configuration
* requests as they pass through.</p>
*
* @since SAX 2.0
* @author David Megginson,
* <a href="mailto:sax@megginson.com">sax@megginson.com</a>
* @version 2.0
* @see org.xml.sax.XMLFilter
* @see org.xml.sax.XMLReader
* @see org.xml.sax.EntityResolver
* @see org.xml.sax.DTDHandler
* @see org.xml.sax.ContentHandler
* @see org.xml.sax.ErrorHandler
*/
public class XMLFilterImpl
implements XMLFilter, EntityResolver, DTDHandler, ContentHandler, ErrorHandler
{
////////////////////////////////////////////////////////////////////
// Constructors.
////////////////////////////////////////////////////////////////////
/**
* Construct an empty XML filter, with no parent.
*
* <p>This filter will have no parent: you must assign a parent
* before you start a parse or do any configuration with
* setFeature or setProperty.</p>
*
* @see org.xml.sax.XMLReader#setFeature
* @see org.xml.sax.XMLReader#setProperty
*/
public XMLFilterImpl ()
{
super();
}
/**
* Construct an XML filter with the specified parent.
*
* @see #setParent
* @see #getParent
*/
public XMLFilterImpl (XMLReader parent)
{
super();
setParent(parent);
}
////////////////////////////////////////////////////////////////////
// Implementation of org.xml.sax.XMLFilter.
////////////////////////////////////////////////////////////////////
/**
* Set the parent reader.
*
* <p>This is the {@link org.xml.sax.XMLReader XMLReader} from which
* this filter will obtain its events and to which it will pass its
* configuration requests. The parent may itself be another filter.</p>
*
* <p>If there is no parent reader set, any attempt to parse
* or to set or get a feature or property will fail.</p>
*
* @param parent The parent XML reader.
* @exception NullPointerException If the parent is null.
* @see #getParent
*/
public void setParent (XMLReader parent)
{
if (parent == null) {
throw new NullPointerException("Null parent");
}
this.parent = parent;
}
/**
* Get the parent reader.
*
* @return The parent XML reader, or null if none is set.
* @see #setParent
*/
public XMLReader getParent ()
{
return parent;
}
////////////////////////////////////////////////////////////////////
// Implementation of org.xml.sax.XMLReader.
////////////////////////////////////////////////////////////////////
/**
* Set the state of a feature.
*
* <p>This will always fail if the parent is null.</p>
*
* @param name The feature name.
* @param state The requested feature state.
* @exception org.xml.sax.SAXNotRecognizedException When the
* XMLReader does not recognize the feature name.
* @exception org.xml.sax.SAXNotSupportedException When the
* XMLReader recognizes the feature name but
* cannot set the requested value.
* @see org.xml.sax.XMLReader#setFeature
*/
public void setFeature (String name, boolean state)
throws SAXNotRecognizedException, SAXNotSupportedException
{
if (parent != null) {
parent.setFeature(name, state);
} else {
throw new SAXNotRecognizedException("Feature: " + name);
}
}
/**
* Look up the state of a feature.
*
* <p>This will always fail if the parent is null.</p>
*
* @param name The feature name.
* @return The current state of the feature.
* @exception org.xml.sax.SAXNotRecognizedException When the
* XMLReader does not recognize the feature name.
* @exception org.xml.sax.SAXNotSupportedException When the
* XMLReader recognizes the feature name but
* cannot determine its state at this time.
* @see org.xml.sax.XMLReader#getFeature
*/
public boolean getFeature (String name)
throws SAXNotRecognizedException, SAXNotSupportedException
{
if (parent != null) {
return parent.getFeature(name);
} else {
throw new SAXNotRecognizedException("Feature: " + name);
}
}
/**
* Set the value of a property.
*
* <p>This will always fail if the parent is null.</p>
*
* @param name The property name.
* @param state The requested property value.
* @exception org.xml.sax.SAXNotRecognizedException When the
* XMLReader does not recognize the property name.
* @exception org.xml.sax.SAXNotSupportedException When the
* XMLReader recognizes the property name but
* cannot set the requested value.
* @see org.xml.sax.XMLReader#setProperty
*/
public void setProperty (String name, Object value)
throws SAXNotRecognizedException, SAXNotSupportedException
{
if (parent != null) {
parent.setProperty(name, value);
} else {
throw new SAXNotRecognizedException("Property: " + name);
}
}
/**
* Look up the value of a property.
*
* @param name The property name.
* @return The current value of the property.
* @exception org.xml.sax.SAXNotRecognizedException When the
* XMLReader does not recognize the feature name.
* @exception org.xml.sax.SAXNotSupportedException When the
* XMLReader recognizes the property name but
* cannot determine its value at this time.
* @see org.xml.sax.XMLReader#setFeature
*/
public Object getProperty (String name)
throws SAXNotRecognizedException, SAXNotSupportedException
{
if (parent != null) {
return parent.getProperty(name);
} else {
throw new SAXNotRecognizedException("Property: " + name);
}
}
/**
* Set the entity resolver.
*
* @param resolver The new entity resolver.
* @exception NullPointerException If the resolver
* is null.
* @see org.xml.sax.XMLReader#setEntityResolver
*/
public void setEntityResolver (EntityResolver resolver)
{
if (resolver == null) {
throw new NullPointerException("Null entity resolver");
} else {
entityResolver = resolver;
}
}
/**
* Get the current entity resolver.
*
* @return The current entity resolver, or null if none was set.
* @see org.xml.sax.XMLReader#getEntityResolver
*/
public EntityResolver getEntityResolver ()
{
return entityResolver;
}
/**
* Set the DTD event handler.
*
* @param resolver The new DTD handler.
* @exception NullPointerException If the handler
* is null.
* @see org.xml.sax.XMLReader#setDTDHandler
*/
public void setDTDHandler (DTDHandler handler)
{
if (handler == null) {
throw new NullPointerException("Null DTD handler");
} else {
dtdHandler = handler;
}
}
/**
* Get the current DTD event handler.
*
* @return The current DTD handler, or null if none was set.
* @see org.xml.sax.XMLReader#getDTDHandler
*/
public DTDHandler getDTDHandler ()
{
return dtdHandler;
}
/**
* Set the content event handler.
*
* @param resolver The new content handler.
* @exception NullPointerException If the handler
* is null.
* @see org.xml.sax.XMLReader#setContentHandler
*/
public void setContentHandler (ContentHandler handler)
{
if (handler == null) {
throw new NullPointerException("Null content handler");
} else {
contentHandler = handler;
}
}
/**
* Get the content event handler.
*
* @return The current content handler, or null if none was set.
* @see org.xml.sax.XMLReader#getContentHandler
*/
public ContentHandler getContentHandler ()
{
return contentHandler;
}
/**
* Set the error event handler.
*
* @param handle The new error handler.
* @exception NullPointerException If the handler
* is null.
* @see org.xml.sax.XMLReader#setErrorHandler
*/
public void setErrorHandler (ErrorHandler handler)
{
if (handler == null) {
throw new NullPointerException("Null error handler");
} else {
errorHandler = handler;
}
}
/**
* Get the current error event handler.
*
* @return The current error handler, or null if none was set.
* @see org.xml.sax.XMLReader#getErrorHandler
*/
public ErrorHandler getErrorHandler ()
{
return errorHandler;
}
/**
* Parse a document.
*
* @param input The input source for the document entity.
* @exception org.xml.sax.SAXException Any SAX exception, possibly
* wrapping another exception.
* @exception java.io.IOException An IO exception from the parser,
* possibly from a byte stream or character stream
* supplied by the application.
* @see org.xml.sax.XMLReader#parse(org.xml.sax.InputSource)
*/
public void parse (InputSource input)
throws SAXException, IOException
{
setupParse();
parent.parse(input);
}
/**
* Parse a document.
*
* @param systemId The system identifier as a fully-qualified URI.
* @exception org.xml.sax.SAXException Any SAX exception, possibly
* wrapping another exception.
* @exception java.io.IOException An IO exception from the parser,
* possibly from a byte stream or character stream
* supplied by the application.
* @see org.xml.sax.XMLReader#parse(String)
*/
public void parse (String systemId)
throws SAXException, IOException
{
parse(new InputSource(systemId));
}
////////////////////////////////////////////////////////////////////
// Implementation of org.xml.sax.EntityResolver.
////////////////////////////////////////////////////////////////////
/**
* Filter an external entity resolution.
*
* @param publicId The entity's public identifier, or null.
* @param systemId The entity's system identifier.
* @return A new InputSource or null for the default.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @exception java.io.IOException The client may throw an
* I/O-related exception while obtaining the
* new InputSource.
* @see org.xml.sax.EntityResolver#resolveEntity
*/
public InputSource resolveEntity (String publicId, String systemId)
throws SAXException, IOException
{
if (entityResolver != null) {
return entityResolver.resolveEntity(publicId, systemId);
} else {
return null;
}
}
////////////////////////////////////////////////////////////////////
// Implementation of org.xml.sax.DTDHandler.
////////////////////////////////////////////////////////////////////
/**
* Filter a notation declaration event.
*
* @param name The notation name.
* @param publicId The notation's public identifier, or null.
* @param systemId The notation's system identifier, or null.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.DTDHandler#notationDecl
*/
public void notationDecl (String name, String publicId, String systemId)
throws SAXException
{
if (dtdHandler != null) {
dtdHandler.notationDecl(name, publicId, systemId);
}
}
/**
* Filter an unparsed entity declaration event.
*
* @param name The entity name.
* @param publicId The entity's public identifier, or null.
* @param systemId The entity's system identifier, or null.
* @param notationName The name of the associated notation.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.DTDHandler#unparsedEntityDecl
*/
public void unparsedEntityDecl (String name, String publicId,
String systemId, String notationName)
throws SAXException
{
if (dtdHandler != null) {
dtdHandler.unparsedEntityDecl(name, publicId, systemId,
notationName);
}
}
////////////////////////////////////////////////////////////////////
// Implementation of org.xml.sax.ContentHandler.
////////////////////////////////////////////////////////////////////
/**
* Filter a new document locator event.
*
* @param locator The document locator.
* @see org.xml.sax.ContentHandler#setDocumentLocator
*/
public void setDocumentLocator (Locator locator)
{
this.locator = locator;
if (contentHandler != null) {
contentHandler.setDocumentLocator(locator);
}
}
/**
* Filter a start document event.
*
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#startDocument
*/
public void startDocument ()
throws SAXException
{
if (contentHandler != null) {
contentHandler.startDocument();
}
}
/**
* Filter an end document event.
*
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#endDocument
*/
public void endDocument ()
throws SAXException
{
if (contentHandler != null) {
contentHandler.endDocument();
}
}
/**
* Filter a start Namespace prefix mapping event.
*
* @param prefix The Namespace prefix.
* @param uri The Namespace URI.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#startPrefixMapping
*/
public void startPrefixMapping (String prefix, String uri)
throws SAXException
{
if (contentHandler != null) {
contentHandler.startPrefixMapping(prefix, uri);
}
}
/**
* Filter an end Namespace prefix mapping event.
*
* @param prefix The Namespace prefix.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#endPrefixMapping
*/
public void endPrefixMapping (String prefix)
throws SAXException
{
if (contentHandler != null) {
contentHandler.endPrefixMapping(prefix);
}
}
/**
* Filter a start element event.
*
* @param uri The element's Namespace URI, or the empty string.
* @param localName The element's local name, or the empty string.
* @param qName The element's qualified (prefixed) name, or the empty
* string.
* @param atts The element's attributes.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#startElement
*/
public void startElement (String uri, String localName, String qName,
Attributes atts)
throws SAXException
{
if (contentHandler != null) {
contentHandler.startElement(uri, localName, qName, atts);
}
}
/**
* Filter an end element event.
*
* @param uri The element's Namespace URI, or the empty string.
* @param localName The element's local name, or the empty string.
* @param qName The element's qualified (prefixed) name, or the empty
* string.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#endElement
*/
public void endElement (String uri, String localName, String qName)
throws SAXException
{
if (contentHandler != null) {
contentHandler.endElement(uri, localName, qName);
}
}
/**
* Filter a character data event.
*
* @param ch An array of characters.
* @param start The starting position in the array.
* @param length The number of characters to use from the array.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#characters
*/
public void characters (char ch[], int start, int length)
throws SAXException
{
if (contentHandler != null) {
contentHandler.characters(ch, start, length);
}
}
/**
* Filter an ignorable whitespace event.
*
* @param ch An array of characters.
* @param start The starting position in the array.
* @param length The number of characters to use from the array.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#ignorableWhitespace
*/
public void ignorableWhitespace (char ch[], int start, int length)
throws SAXException
{
if (contentHandler != null) {
contentHandler.ignorableWhitespace(ch, start, length);
}
}
/**
* Filter a processing instruction event.
*
* @param target The processing instruction target.
* @param data The text following the target.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#processingInstruction
*/
public void processingInstruction (String target, String data)
throws SAXException
{
if (contentHandler != null) {
contentHandler.processingInstruction(target, data);
}
}
/**
* Filter a skipped entity event.
*
* @param name The name of the skipped entity.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ContentHandler#skippedEntity
*/
public void skippedEntity (String name)
throws SAXException
{
if (contentHandler != null) {
contentHandler.skippedEntity(name);
}
}
////////////////////////////////////////////////////////////////////
// Implementation of org.xml.sax.ErrorHandler.
////////////////////////////////////////////////////////////////////
/**
* Filter a warning event.
*
* @param e The nwarning as an exception.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ErrorHandler#warning
*/
public void warning (SAXParseException e)
throws SAXException
{
if (errorHandler != null) {
errorHandler.warning(e);
}
}
/**
* Filter an error event.
*
* @param e The error as an exception.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ErrorHandler#error
*/
public void error (SAXParseException e)
throws SAXException
{
if (errorHandler != null) {
errorHandler.error(e);
}
}
/**
* Filter a fatal error event.
*
* @param e The error as an exception.
* @exception org.xml.sax.SAXException The client may throw
* an exception during processing.
* @see org.xml.sax.ErrorHandler#fatalError
*/
public void fatalError (SAXParseException e)
throws SAXException
{
if (errorHandler != null) {
errorHandler.fatalError(e);
}
}
////////////////////////////////////////////////////////////////////
// Internal methods.
////////////////////////////////////////////////////////////////////
/**
* Set up before a parse.
*
* <p>Before every parse, check whether the parent is
* non-null, and re-register the filter for all of the
* events.</p>
*/
private void setupParse ()
{
if (parent == null) {
throw new NullPointerException("No parent for filter");
}
parent.setEntityResolver(this);
parent.setDTDHandler(this);
parent.setContentHandler(this);
parent.setErrorHandler(this);
}
////////////////////////////////////////////////////////////////////
// Internal state.
////////////////////////////////////////////////////////////////////
private XMLReader parent = null;
private Locator locator = null;
private EntityResolver entityResolver = null;
private DTDHandler dtdHandler = null;
private ContentHandler contentHandler = null;
private ErrorHandler errorHandler = null;
}
// end of XMLFilterImpl.java